Long-Term Regeneration and Functional Recovery of a 15 mm Critical Nerve Gap Bridged by Tremella fuciformis Polysaccharide-Immobilized Polylactide Conduits

Tremella fuciformis polysaccharides induce ferroptosis in Epstein-Barr virus-associated gastric cancer by inactivating NRF2/HO-1 signaling

Approximately 10% of gastric cancers are associated with Epstein-Barr virus (EBV). Tremella fuciformis polysaccharides (TFPs) are characterized by antioxidative and anti-inflammatory effects in different diseases. However, whether TFP improves EBV-associated gastric cancer (EBVaGC) has never been explored. The effects of TFP on EBV-infected GC cell viability were determined using a CCK-8 assay and flow cytometry. Western blotting and RT-qPCR were performed to explore the expression of ferroptosis-related proteins. The CCK-8 assay showed that TFP decreased EBV-infected GC cell viability in a dose- and time-dependent manner. Flow cytometry assays indicated that TFP significantly induced EBV-infected GC cell death. TFP also reduced the migratory capacity of EBV-infected GC cells. Furthermore, treatment with TFP significantly increased the mRNA levels of PTGS2 and Chac1 in EBV-infected GC cells. Western blot assays indicated that TFP suppressed the expression of NRF2, HO-1, GPX4 and xCT in EBV-infected GC cells. More importantly, overexpression of NRF2 could obviously rescue TFP-induced downregulation of GPX4 and xCT in EBV-infected GC cells. In summary, we showed novel data that TFP induced ferroptosis in EBV-infected GC cells by inhibiting NRF2/HO-1 signaling. The current findings may shed light on the potential clinical application of TFP in the treatment of EBVaGC.

Extraction, isolation, purification, derivatization, bioactivity, structure-activity relationship and application of polysaccharides from white jellyfungus

White jellyfungus is one of the most popular nutritional supplements. The polysaccharide (WJP) is an important active component of white jellyfungus, it not only has a variety of biological activities but also is non-toxic to humans. So, many scholars have carried out different researches on WJP. However, the lack of a detailed summary of WJP limits the scale of industrial development of WJP. Herein, the research progress of WJP in extraction, isolation, structure, derivatization and structure-activity relationship was reviewed. Different extraction methods were compared, the activity and application of WJP were summarized, and the structure-activity relationship of WJP was emphasized in order to provide effective theoretical support for improving the utilization of WJP and promoting the application of related industries. This article is protected by copyright. All rights reserved.

Adipose-Derived Mesenchymal Stem Cells From a Hypoxic Culture Improve Neuronal Differentiation and Nerve Repair

Hypoxic expansion has been demonstrated to enhance in vitro neuronal differentiation of bone-marrow derived mesenchymal stem cells (BMSCs). Whether adipose-derived mesenchymal stem cells (ADSCs) increase their neuronal differentiation potential following hypoxic expansion has been examined in the study. Real-time quantitative reverse transcription-polymerase chain reaction and immunofluorescence staining were employed to detect the expression of neuronal markers and compare the differentiation efficiency of hypoxic and normoxic ADSCs. A sciatic nerve injury animal model was used to analyze the gastrocnemius muscle weights as the outcomes of hypoxic and normoxic ADSC treatments, and sections of the regenerated nerve fibers taken from the conduits were analyzed by histological staining and immunohistochemical staining. Comparisons of the treatment effects of ADSCs and BMSCs following hypoxic expansion were also conducted in vitro and in vivo. Hypoxic expansion prior to the differentiation procedure promoted the expression of the neuronal markers in ADSC differentiated neuron-like cells. Moreover, the conduit connecting the sciatic nerve gap injected with hypoxic ADSCs showed the highest recovery rate of the gastrocnemius muscle weights in the animal model, suggesting a conceivable treatment for hypoxic ADSCs. The percentages of the regenerated myelinated fibers from the hypoxic ADSCs detected by toluidine blue staining and myelin basic protein (MBP) immunostaining were higher than those of the normoxic ones. On the other hand, hypoxic expansion increased the neuronal differentiation potential of ADSCs compared with that of the hypoxic BMSCs in vitro. The outcomes of animals treated with hypoxic ADSCs and hypoxic BMSCs showed similar results, confirming that hypoxic expansion enhances the neuronal differentiation potential of ADSCs in vitro and improves in vivo therapeutic potential.

A review on the production, structure, bioactivities and applications of Tremella polysaccharides

Tremella polysaccharide is known to be structurally unique and biologically active natural products, abundant and versatile in activities and applications in food industry, daily chemical industry and medicine industry. In order to improve the industrialisation of Tremella polysaccharide, the limitations of preparation and structure-activity relationship of Tremella polysaccharide were reviewed in this paper. The research progress of Tremella polysaccharide in the past 20 years was summarized from the sources, preparation methods, molecular structure, activity and application, and the research trend in the future was also prospected. The application prospect of Tremella polysaccharide in against multiple sub-health states was worth expecting.

Fabrication of poly (trimethylene carbonate)/reduced graphene oxide-graft-poly (trimethylene carbonate) composite scaffolds for nerve regeneration

One of the key challenges for neural tissue engineering is to exploit functional materials to guide and support nerve regeneration. Currently, reduced graphene oxide (rGO), which is well-known for its unique electrical and mechanical properties, has been incorporated into biocompatible polymers to manufacture functional scaffolds for nerve tissue engineering. However, rGO has poor dispersity in polymer matrix, which limits its further application. Here, we replaced rGO with rGO-graft-PTMC. The rGO-graft-PTMC was firstly prepared by grafting trimethylene carbonate (TMC) oligomers onto rGO. Subsequently, PTMC/rGO-graft-PTMC composite fibrous mats were fabricated by electrospinning of a dispersion of PTMC and rGO-graft-PTMC. The loading of rGO-graft-PTMC could reach up to 6 wt% relative to PTMC. Scanning electron microscopy images showed that the morphologies and average diameters of PTMC/rGO-graft-PTMC composite fibrous mats were affected by the content of rGO-graft-PTMC. Additionally, the incorporation of rGO-graft-PTMC resulted in enhanced thermal stability and hydrophobicity of PTMC fibers. Biological results demonstrated that PC12 cells showed higher cell viability on PTMC/rGO-graft-PTMC fibers of 2.4, 4.0 and 6.0 wt% rGO-graft-PTMC compared to pure PTMC fibers. These results suggest that PTMC/rGO-graft-PTMC composite fibrous structures hold great potential for neural tissue engineering.

Evaluation of nerve growth factor (NGF) treated mesenchymal stem cells for recovery in neurotmesis model of peripheral nerve injury

BACKGROUND

Peripheral nerve damages are a relatively common type of the nervous system injuries. Although peripheral nerves show some capacity of regeneration after injury, the extent of regeneration is not remarkable. The present study aimed to evaluate the effect of NGF treated mesenchymal stem cells on regeneration of transected sciatic nerve.

MATERIALS AND METHODS

In this experimental study, forty-two male Wistar.rats (180-200 g) were randomly divided into 6 groups (n = 7) including control, Membrane + Cell (Mem + Cell), NGF group, NGF + Cell group, NGF + Mem group and NGF + Mem + Cell group. Regeneration of sciatic nerve was evaluated using behavioral analysis, electrophysiological assessment and histological examination.

RESULTS

The rats in the NGF + Mem + Cell group showed significant decrease in sciatic functional index (SFI) and hot water paw immersion test during the 2nd to 8th weeks after surgery. (p < 0.001). At 8 weeks after surgery, electrophysiological findings showed that amplitude increased and latency decreased significantly in NGF + Mem + Cell group (p < 0.001). Measured histological parameters showed that number of nerve fibers, number of vessels and percent of vessel area also increased significantly in NGF + Mem + Cell group (p < 0.05).

CONCLUSION

The present study showed that NGF in accompany with mesenchymal stem cells improved electrophysiological and histological indices.

Progress in the Research and Development of Nerve Conduits

The reconstruction after peripheral nerve damage, especially for long-segment nerve defects, remains a clinical challenge. Autologous nerve graft transplantation is an efficient method for the repair of peripheral nerve defects, but the involved complications and shortcomings have greatly limited the clinical efficacy of treatments offered to patients with nerve defects. Thus, there is an urgent need to develop new therapeutic strategies and explore alternatives to autologous nerve transplantation in clinical practice, based on the knowledge of the peripheral nerve regeneration mechanism and biological histocompatibility principles. With significant advances in the research and application of nerve conduits, they have been used to repair peripheral nerve injury for several decades. In this paper, the study background of nerve conduits, their applications in clinic, status of conduit material research and construction of tissue-engineered artificial nerves were reviewed.